[Gdal-dev] Question on building external overviews - SOLVED

[Stephen Woodbridge]

Stephen Woodbridge wrote:
> Frank Warmerdam wrote:
>> Stephen Woodbridge wrote:
>>> Hi guys,
>>>
>>> I took this approach to building external overviews, but all my 
>>> images seem to be gray in mapserver and appear to be all nodata 
>>> values in the file. Any idea what I'm doing wrong here?
>>>
>>> I have a directory of of 16x16 tiles that fill a one degree block.
>>> I want to make 4x4 overview files with 4x4 of the original tiles.
>>> ie: 4x4 original tiles into 1 overview
>>>
>>> So for the first tile, I create the output tile like this
>>>
>>> gdal_translate -of GTiff -co \"TILED=YES\" -outsize 3200 3200 -a_srs 
>>> EPSG:4326 -a_nodata 0 -a_ullr $top $left $bot $right $inf $outf
> 
> I set $top $left $bot $right to the extents shown in the gdalinfo in the 
> prior post, which is 4 times larger in x and y then the original tiles 
> and $inf is one of the original tiles that is 1/16 the size of the 
> output area.

I feel stupid for not reading the manual <sigh>

    -a_ullr $top $left $bot $right

should be

    -a_ullr $left $top $right $bot

-Steve